Photo Gallery: Marine Microbes

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Protoperidinium Pellucidum

Photograph by Stephanie Valentin and David Patterson, micro*scope

Microbes, like this single-celled marine phytoplankton, make up a staggering 90 percent of the ocean’s total biomass. Because such organisms are so difficult to observe in nature, much of the ocean’s microbial life remains a mystery to science.

Lyngbya

Photograph by David Patterson, micro*scope

The ropelike coils of these filamentous cyanobacteria, found in a New England salt marsh, are created when many disc-shaped cells join end-to-end. Cyanobacteria, which use photosynthesis to produce oxygen, are the oldest known forms of life on Earth. They appeared in the fossil record over three billion years ago and laid the biological groundwork for today’s plants.

Thalassionema

Photograph by David Patterson, micro*scope

This star-shaped colony of marine diatoms is called Thalassionema. Diatoms are single-celled algae and some of the most numerous photosynthetic “plants” in the oceans. Hundreds of diatoms can fit on the head of a pin, but these tiny organisms exist in countless numbers—enough to change seawater color during periodic population “blooms.”

Merismopedia

Photograph by David Patterson, micro*scope

Like a microscopic (and monochromatic) version of Tetris, Merismopedia cells form square-packed colonies. These cyanobacteria, plucked from a New England salt marsh, were flooded with ultraviolet light that was later filtered out of the image to reveal a red hue produced by chlorophyll molecules inside the cells.

Bacillaria Paxillifer

Photograph by David Patterson and Bob Andersen, micro*scope

This living colony of planktonic diatoms includes many individual cells joined by the slits in their valve faces, called raphes, which allow them to move. Thus linked, the cells slide against one another to alternately extend and contract the entire colony and move it with an accordionlike motion unique among the diatoms.

Pyrocystis Lunula

Photograph by David Patterson and Bob Andersen, micro*scope

Pyrocystis lunula is a bioluminescent dinoflagellate that typically appears in a moonlike crescent shape. Here, however, the cell has been caught in the act of reproduction by division. Two nuclei are visible, one seen above and the other below the central knot of plastid organelles, which keys metabolic activities like photosynthesis.

Dinoflagellate

Photograph by Stephanie Valentin and David Patterson, micro*scope

A scanning electron microscope captured this pair of unicellular dinoflagellates in a drop of seawater found near the Opera House in Sydney, Australia. The microbes were later colorized to produce this image’s glowing, green hue. Scientists are just beginning to understand the impact such invisible organisms can have, for good or ill. Dinophysis species like these are associated with diarrhetic shellfish poisoning.

Cryptopharynx

Photograph by David Patterson, micro*scope

Most people tend to think of marine microbes, if they think of them at all, as simply drifting wherever ocean currents take them. Many do just that, but others are more active. The surface of this Cryptopharynx cell is covered with thin, hairlike cilia, which enable it to move over seafloor sand and mud.

Astrolithium

Photograph by David Patterson, micro*scope

Microbes are the oldest form of life on Earth—and for about 75 percent of the planet’s history they were the only kind of life. Today multicellular species may top the food chain but they remain dependent upon microbes for survival. Should something happen to higher life-forms, on the other hand, microbes would probably exist quite well on their own, as they did for eons when the planet was young.

Karenia Brevis

Photograph by David Patterson, micro*scope

The ocean’s surface is home to a vast array of microbes that help to regulate the chemistry of both the sea and Earth’s atmosphere by passing gases from water to air and vice versa. Many microbes are beneficial, but others, including Karenia brevis, can pose problems. The toxic dinoflagellate is linked to dangerous “red tide” outbreaks in the Gulf of Mexico.

Engage, Conserve, Restore

The National Geographic Society’s freshwater initiative is a multi-year global effort to inspire and empower individuals and communities to conserve freshwater and preserve the extraordinary diversity of life that rivers, lakes, and wetlands sustain.